Method for manufacturing a capacitor of a semiconductor device

ABSTRACT

A capacitor of a semiconductor device includes a first interlayer dielectric film pattern formed on a semiconductor substrate and having a first contact hole therein and a contact plug buried in the first contact hole and electrically connected to the semiconductor substrate. A diffusion barrier layer pattern is formed on the contact plug, and a first conductive film pattern is formed on the diffusion barrier layer pattern for preventing the oxidization of the diffusion barrier layer pattern. A second interlayer dielectric pattern having a second contact hole exposing the surface of the first conductive film pattern is formed on the first interlayer dielectric film pattern and the first conductive film pattern. A second conductive film pattern used as the lower electrode of a capacitor is buried in the second contact hole and connected to the first conductive film pattern. A high dielectric film and a third conductive film pattern used as the upper electrode of the capacitor are sequentially formed so as to surround the second conductive film patter. The first conductive film pattern is formed of a platinum group metal or an oxide conductor including the platinum group metal. According to the present invention, it is possible to prevent the increase of a contact resistance since a diffusion barrier layer pattern is not oxidized due to a first conductive film pattern.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly, to a capacitor of a semiconductor device including a dielectric film of high dielectric constant (a high dielectric film) and a method for manufacturing the same.

[0003] 2. Description of the Related Art

[0004] As an integration density of a semiconductor device such as a dynamic random access memory (DRAM) and a ferro-electric RAM (FRAM) increases, a high dielectric film such as PbZrTiO₃ (PZT) and BaSrTiO₃ (BST) is used as the dielectric film of a capacitor. Metals of the platinum group and the oxide thereof are mainly used as the conductive film consisting of a lower electrode or an upper electrode in a capacitor using the high dielectric film. Here, a dry etching for forming patterns of the platinum group and the oxide thereof used as the conductive film of the capacitor is difficult. Also, since the platinum group and the oxide thereof reacts with a polysilicon film used as a semiconductor substrate or a contact plug, a diffusion barrier layer for preventing an interaction is required between the conductive film used as the capacitor and the polysilicon film.

[0005]FIG. 1 is a sectional view for describing the capacitor of the semiconductor device according to the conventional technology.

[0006] To be specific, an interlayer dielectric film 3 having a contact hole is formed on a semiconductor substrate 1. A contact plug 5 comprised of the polysilicon film is buried in the contact hole. A diffusion barrier layer 7 connected to the contact plug 5 and comprised of Ta is formed. A first conductive film 9 used as the lower electrode of the capacitor and comprised of Pt is formed on the diffusion barrier layer 7. A high dielectric film 11 is formed on the overall surface of the semiconductor substrate 1 on which the first conductive material 9 is formed. A second conductive material 13 used as an upper electrode is formed on the overall surface of the semiconductor substrate 1 on which the high dielectric film 11 is formed.

[0007] In a conventional capacitor shown in FIG. 1, the diffusion barrier layer 7 is formed in order to prevent the reaction between the platinum film of the first conductive film 9 and the contact plug 5. In the conventional capacitor shown in FIG. 1, since the side surfaces of the platinum film of the first conductive film 9 and the diffusion barrier layer 7 are exposed during the deposition of the dielectric film 11 or in a subsequent heat treatment process, the diffusion barrier layer 7 is oxidized and thus becoming Ta₂O₅ which is a non-conductor. Accordingly, the contact resistance of the first conductive film 9 increases and the first conductive film 9 cannot be used. Also, in the conventional capacitor shown in FIG. 1, leakage current increases since the diffusion barrier layer 7 reacts with the high dielectric film 11.

[0008] A method of recessing the contact plug is proposed in order to solve the above problem, which will be described with reference to FIGS. 2 and 3.

[0009]FIGS. 2 and 3 are sectional views showing the capacitors of the semiconductor device according to other conventional technology.

[0010] Referring to FIGS. 2 and 3, an interlayer dielectric film 23 having a contact hole is formed on a semiconductor substrate 21. A silicon plug 25 and a diffusion barrier layer 27 comprised of Ta film are sequentially buried in the contact hole. A first conductive film 29 used as the lower electrode of the capacitor and comprised of Pt film is formed on the diffusion barrier layer 27.

[0011] In the conventional capacitor shown in FIG. 2, the diffusion barrier layer 27 is formed in a position different from that of the diffusion barrier layer 7 of FIG. 1. Namely, since the diffusion barrier layer 27 is buried in the contact hole, it is possible to prevent the side surface of the diffusion barrier layer 27 from being exposed.

[0012] However, in the conventional capacitor shown in FIG. 2, since a diffusion path of an oxygen atom is short, and thus the diffusion barrier layer 27 may be oxidized during a subsequent process of forming the high dielectric film.

[0013] Furthermore, in the conventional capacitor as shown in FIG. 3, when a misalign is occurred during performing patterning for forming the first conductive film 29, the diffusion barrier layer 27 is oxidized during the subsequent process of depositing the high dielectric film and becomes a nonconductor. When the diffusion barrier layer 27 becomes the nonconductor, the contact resistance of the conductive film 29 is increased and the production yield of the semiconductor device is deteriorated.

SUMMARY OF THE INVENTION

[0014] Accordingly, it is an object of the present invention to provide a capacitor of a semiconductor device in which it is possible to prevent a contact resistance from increasing by preventing the oxidization of a diffusion barrier layer in employing a high dielectric film.

[0015] It is another object of the present invention to provide a method for manufacturing the capacitor of the above semiconductor device.

[0016] To achieve the first object, a capacitor of a semiconductor device includes a first interlayer dielectric film pattern formed on a semiconductor substrate and having a first contact hole therein and a contact plug buried in the first contact hole and electrically connected to the semiconductor substrate. A diffusion barrier layer pattern is formed on the contact plug, and a first conductive film pattern is formed on the diffusion barrier layer pattern for preventing the oxidization of the diffusion barrier layer pattern. A second interlayer dielectric pattern having a second contact hole exposing the surface of the first conductive film pattern is formed on the first interlayer dielectric film pattern and the first conductive film pattern. A second conductive film pattern used as the lower electrode of a capacitor is buried in the second contact hole and connected to the first conductive film pattern. A high dielectric film and a third conductive film pattern used as the upper electrode of the capacitor are sequentially formed so as to surround the second conductive film patter.

[0017] The diffusion barrier layer pattern can be formed of Ta, Ti, W, Co, Ir, Ru, TaSi, CoSi, TiSi_(x), WSi, TiSiN, TaSiN, IrO₂, RuO₂, WN, TiN, TaN, TaAIN, or TiAIN. The first conductive film pattern can be formed of a platinum group metal or an oxide conductor including the platinum group metal. The contact plug can be formed of a polysilicon film, a silicon film, a tungsten film, a tungsten nitride film, and a titanium nitride film.

[0018] In accordance with an embodiment of the present invention, a capacitor of a semiconductor device includes a first interlayer dielectric film pattern formed on a semiconductor substrate and having a first contact hole therein and a contact plug buried in the first contact hole and electrically connected to the semiconductor substrate. A diffusion barrier layer pattern is formed on the contact plug, and a first conductive film pattern is formed on the diffusion barrier layer pattern for preventing the oxidization of the diffusion barrier layer pattern. A second interlayer dielectric film pattern having a second contact hole for exposing the surface of the first conductive film pattern is formed on the first interlayer dielectric film pattern and the first conductive film pattern. A second conductive film pattern used as the lower electrode of the capacitor is formed on the inner wall of the second contact hole and on the first conductive film pattern. A high dielectric film and a third conductive film pattern used as the upper electrode are sequentially formed on the second conductive film pattern and the second interlayer dielectric film pattern.

[0019] To achieve the second object, a method for manufacturing a capacitor of a semiconductor device includes the step of forming a first interlayer dielectric film pattern having a first contact hole for exposing the surface of a semiconductor substrate on the semiconductor substrate. a contact plug buried in the first contact hole and electrically connected to the semiconductor substrate is formed. A diffusion barrier layer pattern and a first conductive film pattern for exposing the surface of the first interlayer dielectric film pattern are sequentially formed on the contact plug. A second interlayer dielectric film pattern having a second contact hole for exposing the surface of the first conductive film pattern is formed on the first interlayer dielectric film pattern and the first conductive film pattern. A second conductive film pattern used as the lower electrode of a capacitor so as to be buried in the second contact hole is formed on the first conductive film pattern. A high dielectric film and a third conductive film pattern used as the upper electrode of a capacitor are sequentially formed on the second conductive film pattern.

[0020] The contact plug is achieved by the steps of forming a conductive film on a substrate in which the first contact hole and the first interlayer dielectric film pattern are formed; and etching back or performing a CMP process on the conductive film. The diffusion barrier layer pattern can be formed of Ta, Ti, W, Co, Ir, Ru, TaSi, CoSi, TiSi_(x), WSi, TiSiN, TaSiN, IrO₂, RuO₂, WN, TiN, TaN, TaAIN, or TiAIN. The first conductive film pattern can be formed of a platinum group metal or an oxide conductor including the platinum group metal.

[0021] In accordance with an embodiment of the present invention, a method for manufacturing a capacitor of a semiconductor device includes the step of forming a first interlayer dielectric film pattern having a first contact hole for exposing the surface of a semiconductor substrate on the semiconductor substrate. Next, a contact plug buried in the first contact hole and electrically connected to the semiconductor substrate is formed. A diffusion barrier layer pattern and a first conductive film pattern for exposing the first interlayer dielectric film pattern are sequentially formed on the contact plug. A second interlayer dielectric film pattern having a second contact hole for exposing the surface of the first conductive film pattern is formed on the first interlayer dielectric film pattern and the first conductive film pattern. A second conductive film pattern used as the lower electrode of the capacitor is formed on the inner wall of the second contact hole and on the surface of the first conductive film pattern. A high dielectric film and a third conductive film pattern used as the upper electrode of the capacitor are sequentially formed on the second conductive film pattern.

[0022] The second conductive film pattern is achieved by the steps of forming a conductive film on the overall surface of the resultant in which the second contact hole is formed, forming a material film on the overall surface of the resultant on which the conductive film is formed so as to bury the second contact hole, etching back or performing a CMP process on the material film and the conductive film so as to expose the second interlayer dielectric film pattern, and removing a material film left in the second contact hole.

[0023] The material film can be formed of a photoresist film or an insulating film. The second conductive film pattern is achieved by the steps of forming a conductive film on the overall surface of the resultant in which the second contact hole is formed, and performing a CMP process on the conductive film so as to expose the second interlayer dielectric film pattern.

[0024] According to the present invention, the diffusion barrier layer pattern is not oxidized since it is formed under the first conductive film pattern. Accordingly, it is possible to prevent the increase of the contact resistance.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above objects and advantages of the present invention will become more apparent by describing in detail a preferred embodiment thereof with reference to the attached drawings in which:

[0026]FIG. 1 is a sectional view for describing a capacitor of a semiconductor device according to the conventional technology;

[0027]FIGS. 2 and 3 are sectional views for describing capacitors of a semiconductor device according to other conventional technology;

[0028]FIG. 4 is a sectional view for describing a capacitor of a semiconductor according to a first embodiment of the present invention;

[0029]FIG. 5 is a sectional view for describing a capacitor of a semiconductor device according to a second embodiment of the present invention;

[0030]FIGS. 6 through 10 are sectional views for describing a method for manufacturing a capacitor of a semiconductor device according to the present invention shown in FIG. 4; and

[0031]FIGS. 11 through 13 are sectional views for describing a method for manufacturing the capacitor of the semiconductor device according to the present invention shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032]FIG. 4 is a sectional view for describing a capacitor of a semiconductor device according to a first embodiment of the present invention.

[0033] To be specific, a first interlayer dielectric film pattern 33 having a first contact hole 34 inside thereof is formed on a semiconductor substrate 31, for example, a silicon substrate. A contact plug 35 electrically connected to the semiconductor substrate 31 is formed in the first contact hole 34. The contact plug 35 is comprised of a polysilicon film, a silicon film, a tungsten film, a tungsten nitride film, or a titaninum nitride film. A diffusion barrier layer pattern 37 and a first conductive film pattern 39 are sequentially formed on the contact plug 35 and the first interlayer dielectric film pattern 33 so as to be connected to the contact plug 35. The first conductive film pattern 39 is formed to prevent the diffusion barrier layer pattern 37 from being oxidized. The diffusion barrier layer pattern 37 is formed of Ta, Ti, W, Co, Ir, Ru, TaSi, CoSi, TiSi_(x), WSi, TiSiN, TaSiN, IrO₂, RuO₂, WN, TiN, TaN, TaAIN, or TaAIN. The first conductive film pattern 39 is comprised of a platinum group metal such as Pt, Ru, and Ir, a platinum group oxide conductor such as IrO₂ and RuO₂, or an oxide conductor including the platinum group metal and having a perovskite structure, such as SrRuO₃, CaSrRuO₃, and BaSrRuO₃.

[0034] A second interlayer dielectric film pattern 41 having a second contact hole 40 for exposing the surface of the first conductive film pattern 39 is formed on the first interlayer dielectric film pattern 33 and the first conductive film pattern 39. A second conductive film pattern 43 used as the lower electrode of the capacitor is formed to be buried in the second contact hole 40 and connected to the first conductive film pattern 39. A high dielectric film 45 is formed so as to surround the second conductive film pattern 43. The high dielectric film 45 is comprised of Al₂O₃, Ta₂O₅, (Ba,Sr)TiO₃, BaTiO₃, SrTiO₃, PbTiO₃, Pb(Zr,Ti)O₃, (Pb,La)TiO₃, KNO₃, or LiNbO₃. A third conductive film pattern 47 used as the upper electrode of the capacitor is formed on the high dielectric film 45. The second conductive film pattern 43 and the third conductive film pattern 47 are comprised of a platinum group metal such as Pt, Ru, and Ir, a platinum group oxide conductor such as IrO₂ and RuO₂, or an oxide conductor including the platinum group metal and having a perovskite structure, such as SrRuO₃, CaSrRuO₃, and BaSrRuO₃, respectively.

[0035] In particular, since the diffusion barrier layer pattern 37 is buried under the first conductive film pattern 39 in the capacitor of the semiconductor device according to the present invention shown in FIG. 4, it is not exposed during the formation of the high dielectric film 45 and the subsequent heat treatment.

[0036] Furthermore, in the capacitor of the semiconductor device according to the present invention shown in FIG. 4, it is possible to control the diffusion path of the oxygen atom by controlling the height (the thickness) of the first conductive film pattern 39 formed on the diffusion barrier layer pattern 37. Therefore, it is not required to increase the height (the thickness) of the second contact hole 40 formed in the second interlayer dielectric film pattern 41. In this case, in a highly integrated semiconductor device, it is possible to bury the second conductive film such as the platinum group metal and the oxide thereof in the second contact hole 40 not by a CVD (chemical vapor deposition) method which has a high process cost and not well developed but by a sputtering method. As a result, the capacitor of the semiconductor device according to the present invention prevents the oxidization of the diffusion barrier layer pattern 37 and reduces a contact resistance.

[0037]FIG. 5 is a sectional view for describing a capacitor of a semiconductor device according to a second embodiment of the present invention. In FIG. 5, reference numerals identical to those of FIG. 4 denote identical members.

[0038] To be specific, in the capacitor of the semiconductor device according to the second embodiment of the present invention, as shown in FIG. 4, the first interlayer dielectric film pattern 33 having a first contact hole 34, a contact plug 35 buried in the first contact hole 43, the diffusion barrier layer pattern 37, and the first conductive film pattern 39 are formed on the semiconductor substrate 31. The height (the thickness) of a second dielectric film pattern 51 having the second contact hole 42 exposing the first conductive film pattern 39 is formed to be high. The second conductive film pattern 53 used as the lower electrode of the capacitor is formed on the inner wall of the second contact hole 42 and on the first conductive film pattern 39. A high dielectric film 55 and a third conductive film pattern 57 used as the upper electrode are formed on the second conductive film pattern 53. The second conductive film pattern 53 and the third conductive film pattern 57 are comprised of a platinum group metal such as Pt, Ru, and Ir, a platinum group oxide conductor such as IrO₂ and RuO₂, or an oxide conductor including the platinum group metal and having a perovskite structure, such as SrRuO₃, CaSrRuO₃, and BaSrRuO₃, respectively. A high dielectric film 55 is comprised of Al₂O₃, Ta₂O₅, (Ba,Sr)TiO₃, BaTiO₃, SrTiO₃, PbTiO₃, Pb(Zr,Ti)O₃, (Pb,La)TiO₃, KNO₃, or LiNbO₃.

[0039] In particular, in the capacitor of the semiconductor device according to the second embodiment of the present invention shown in FIG. 5, the diffusion barrier layer pattern 37 is not exposed during the formation of the high dielectric film 45 and the subsequent process of heat treatment since it is buried under the first conductive film pattern 39 like in FIG. 4 and a oxygen diffusion path is long due to the first conductive film pattern 39.

[0040] In the capacitor of the semiconductor device according to the second embodiment of the present invention shown in FIG. 5, the second interlayer dielectric film pattern 51 is higher than that of FIG. 4. The second conductive film pattern 53 used as the lower electrode is not formed by a dry etching process but by a CMP (chemical mechanical polishing) method or an etch back method. When the second conductive film pattern 43 (FIG. 4) used as the lower electrode comprised of the platinum group metal or the oxide thereof becomes higher since the semiconductor device is highly integrated, it is not possible to form the second conductive film pattern having a height of at least 300 nm under 0.3 um pitch.

[0041]FIGS. 6 through 10 are sectional views for describing a method for manufacturing the capacitor of the semiconductor device according to the present invention shown in FIG. 4.

[0042] In FIG. 6, the first interlayer dielectric film pattern 33 having the first contact hole 34 is formed by forming an insulating film on the semiconductor substrate 31, for example, the silicon substrate and patterning it.

[0043] In FIG. 7, after forming a conductive film used as the contact plug on the substrate in which the first contact hole 34 and the first interlayer dielectric film pattern 33 are formed, the inside of the first contact hole 34 is buried by etching back or performing CMP on the conductive film and thus the contact plug 35 electrically connected to the semiconductor substrate 31 is formed. The contact plug 35 is formed of a polysilicon film, a silicon film, a tungsten film, a tungsten nitride film, or a titanium nitride film. An ohmic layer may be further formed on the contact plug in order to reduce resistance. A metal film having a high melting point such as Co and Ta, a metal nitride film, and a TiW film can be used as the ohmic layer.

[0044] In FIG. 8, the diffusion barrier layer pattern 37 and the first conductive film pattern 39 for exposing the surface of the first interlayer dielectric pattern 33 are formed on the contact plug 35 by sequentially forming the diffusion barrier layer and the conductive film to have thicknesses of 300 to 500 Å and 500 to 1,500 Å on the overall surface of the resultant on which the contact plug film 35 is formed and patterning the diffusion barrier layer and the conductive film using a photolithography and etching processes. The diffusion barrier layer pattern 37 is formed of one selected from the group consisting of Ta, Ti, W, Co, Ir, Ru, TaSi, CoSi, TiSi_(x), WSi, TiSiN, TaSiN, IrO₂, RuO₂, WN, TiN, TaN, TaAIN, and TiAIN. The first conductive film pattern 39 is comprised of a platinum group metal such as Pt, Ru, and Ir, a platinum group oxide conductor such as IrO₂ and RuO₂, or an oxide conductor including the platinum group metal and having a perovskite structure such as SrRuO₃, CaSrRuO₃, and BaSrRuO₃.

[0045] In FIG. 9, a second interlayer dielectric film pattern 41 having a second contact hole 40 exposing the surface of the first conductive film pattern 39 is formed by forming an insulating film on the overall surface of the substrate 31 so as to fill a space between the diffusion barrier layer pattern 37 and the first conductive film pattern 39 using a chemical vapor deposition (CVD) method, an LPCVD (low pressure CVD) method, or a PECVD (plasma enhanced CVD) method and patterning the insulating film. The second interlayer dielectric film pattern 41 is formed of undoped silicate glass (USG), spin on glass (SOG), or boro phospho silicate glass (BPSG).

[0046] In FIG. 10, a second conductive film pattern 43 used as the lower electrode of the capacitor is formed on the first conductive film pattern 39 by forming a conductive film on the overall surface of the substrate 31 on which the first conductive film pattern 39 and the second interlayer dielectric film pattern 41 are formed to have a thickness of 3,000 to 7,000 Å and patterning the conductive film. The second conductive film pattern 43 is comprised of a platinum group metal such as Pt, Ru, and Ir, a platinum group oxide conductor such as IrO₂ and RuO₂, or an oxide conductor including the platinum group metal such as SrRuO₃, CaSrRuO₃, and BaSrRuO₃ and having a perovskite structure.

[0047] As shown in FIG. 4, a high dielectric film 45 is formed on the overall surface of the resultant on which the second conductive film pattern 43 is formed. The high dielectric film 45 is formed of Al₂O₃, Ta₂O₅, (Ba,Sr)TiO₃, BaTiO₃, SrTiO₃, PbTiO₃, PbTiO₃, Pb(Zr,Ti)O₃, (Pb,La)TiO₃, KNO₃, or LiNbO₃. The high dielectric film 45 is formed of a sputtering method and the CVD method. The capacitor of the semiconductor device is completed by forming a third conductive film pattern 47 used as the upper electrode of the capacitor on the high dielectric film 45. The third conductive film pattern 47 is comprised of a platinum group metal such as Pt, Ru, and Ir, a platinum group oxide conductor such as IrO₂ and RuO₂, an oxide conductor including the platinum group metal such as SrRuO₃, CaSrRuO₃, and BaSrRuO₃ and having a perovskite structure, or a metal having a high melting point such as W and TiN.

[0048]FIGS. 11 through 13 are sectional views for describing an example of a method for manufacturing the capacitor of the semiconductor device according to the present invention shown in FIG. 5.

[0049] To be specific, manufacturing processes of FIGS. 6 through 8 are proceeded. By doing so, the first interlayer dielectric film pattern 33, the contact plug 35, the diffusion barrier layer pattern 37, and the first conductive film pattern 39 are formed on the semiconductor substrate 31 as shown in FIG. 8.

[0050] Referring to FIG. 11, a second interlayer dielectric film pattern 51 having the second contact hole 42 exposing the first conductive film pattern 39 is formed by forming an insulating film on the overall surface of the resultant on which the first conductive film pattern 39 is formed and patterning the insulating film. The second interlayer dielectric film pattern 51 is formed to be high unlike the second interlayer dielectric film pattern 41 shown in FIG. 9.

[0051] Referring to FIG. 12, a second conductive film 52 used as the lower electrode of the capacitor is formed to have a thickness of 50 to 500 Å on the overall surface of the resultant on which the second interlayer dielectric film pattern 51 is formed. The second conductive film 52 is comprised of a platinum group metal such as Pt, Ru, and Ir, a platinum group oxide conductor such as IrO₂ and RuO₂, an oxide conductor including the platinum group metal such as SrRuO₃, CaSrRuO₃, and BaSrRuO₃ and having a perovskite structure, or a metal having a high melting point such as W and TiN.

[0052] Referring to FIG. 13, a material film 54 burying the second contact hole 42 is formed of a photoresist film or an insulating film on the overall surface on which the second conductive film 52 is formed.

[0053] Referring to FIG. 14, a second conductive film pattern 53 for exposing the second interlayer dielectric film pattern 51 is formed by etching back or performing the CMP method on the material film 54 and the second conductive film 52. Then, the material film 54 left in the second contact hole 42 is removed. By doing so, the second conductive film pattern 53 used as the lower electrode of the capacitor is formed on the inner wall of the second contact hole and on the first conductive film pattern 39.

[0054] When the second conductive film pattern 53 is formed by the CMP method, the material film 54 may not be used. Namely, when the CMP process is performed on the second conductive film 52 without forming the material film, the second conductive film pattern used as the lower electrode of the capacitor is formed on the inner wall of the second contact hole and on the first conductive film pattern 39.

[0055] As shown in FIG. 5, a high dielectric film 55 and a third conductive film pattern 57 used as the upper electrode 57 are formed on the second conductive film pattern 53. The high dielectric film 55 is formed of Al₂O₃, Ta₂O₅, (Ba,Sr)TiO₃, BaTiO₃, SrTiO₃, PbTiO₃, PbTiO₃, Pb(Zr,Ti)O₃, (Pb,La)TiO₃, KNO₃, or LiNbO₃. The third conductive film pattern 57 is comprised of a platinum group metal such as Pt, Ru, and Ir, a platinum group oxide conductor such as IrO₂ and RuO₂, an oxide conductor including the platinum group metal such as SrRuO₃, CaSrRuO₃, and BaSrRuO₃ and having a perovskite structure, or a metal having a high melting point such as W and TiN.

[0056] According to the present invention, it is possible to prevent the increase of the contact resistance since the diffusion barrier layer pattern is not oxidized by the first conductive film pattern when the high dielectric film is used as the dielectric film of the capacitor.

[0057] The present invention is not restricted to the above embodiments, and it is clearly understood that many variations are possible within the scope and spirit of the present invention by anyone skilled in the art. 

What is claimed is:
 1. A capacitor of a semiconductor device, comprising: a first interlayer dielectric film pattern formed on a semiconductor substrate and having a first contact hole therein; a contact plug buried in the first contact hole and electrically connected to the semiconductor substrate; a diffusion barrier layer pattern formed on the contact plug; a first conductive film pattern formed on the diffusion barrier layer pattern for preventing the oxidization of the diffusion barrier layer pattern; a second interlayer dielectric pattern having a second contact hole exposing the surface of the first conductive film pattern on the first interlayer dielectric film pattern and the first conductive film pattern; a second conductive film pattern used as the lower electrode of a capacitor buried in the second contact hole and connected to the first conductive film pattern; and a high dielectric film and a third conductive film pattern used as the upper electrode of the capacitor sequentially formed so as to surround the second conductive film patter
 2. The capacitor of claim 1 , wherein the diffusion barrier layer pattern is formed of one selected from the group consisting of Ta, Ti, W, Co, Ir, Ru, TaSi, CoSi, TiSi_(x), WSi, TiSiN, TaSiN, IrO₂, RuO₂, WN, TiN, TaN, TaAIN, and TiAIN.
 3. The capacitor of claim 1 , wherein the first conductive film pattern is formed of a platinum group metal or an oxide conductor including the platinum group metal.
 4. The capacitor of claim 3 , wherein the platinum metal is Pt, Ru, or Ir and the oxide conductor is IrO₂, RuO₂, SrRuO₃, CaSrRuO₃, or BaSrRuO₃.
 5. The capacitor of claim 1 , wherein the contact plug is formed of one selected from the group consisting of a polysilicon film, a silicon film, a tungsten film, a tungsten nitride film, and a titanium nitride film.
 6. The capacitor of claim 1 , wherein the high dielectric film is formed of one selected from the group consisting of Al₂O₃, Ta₂O₅, (Ba,Sr)TiO₃, BaTiO₃, SrTiO₃, PbTiO₃, PbTiO₃, Pb(Zr,Ti)0 ₃, (Pb,La)TiO₃, KNO₃, or LiNbO₃.
 7. The capacitor of claim 1 , wherein the second conductive film pattern and the third conductive film pattern are comprised of a platinum group metal or an oxide conductor including the platinum metal.
 8. A capacitor of a semiconductor device, comprising: a first interlayer dielectric film pattern formed on a semiconductor substrate and having a first contact hole therein; a contact plug buried in the first contact hole and electrically connected to the semiconductor substrate; a diffusion barrier layer pattern formed on the contact plug; a first conductive film pattern formed on the diffusion barrier layer pattern for preventing the oxidization of the diffusion barrier layer pattern; a second interlayer dielectric film pattern having a second contact hole for exposing the surface of the first conductive film pattern on the first interlayer dielectric film pattern and the first conductive film pattern; a second conductive film pattern used as the lower electrode of the capacitor formed on the inner wall of the second contact hole and on the first conductive film pattern; and a high dielectric film and a third conductive film pattern used as the upper electrode sequentially formed on the second conductive film pattern and the second interlayer dielectric film pattern.
 9. The capacitor of claim 8 , wherein the diffusion barrier layer pattern is formed of one selected from the group consisting of Ta, Ti, W, Co, Ir, Ru, TaSi, CoSi, TiSi_(x), WSi, TiSiN, TaSiN, IrO₂, RuO₂, WN, TIN, TaN, TaAiN, and TiAIN.
 10. The capacitor of claim 8 , wherein the first conductive film pattern is formed of a platinum group metal or an oxide conductor including the platinum group metal.
 11. A method for manufacturing a capacitor of a semiconductor device, comprising the steps of: forming a first interlayer dielectric film pattern having a first contact hole for exposing the surface of a semiconductor substrate on the semiconductor substrate; forming a contact plug buried in the first contact hole and electrically connected to the semiconductor substrate; sequentially forming a diffusion barrier layer pattern and a first conductive film pattern for exposing the surface of the first interlayer dielectric film pattern on the contact plug; forming a second interlayer dielectric film pattern having a second contact hole for exposing the surface of the first conductive film pattern on the first interlayer dielectric film pattern and the first conductive film pattern; forming a second conductive film pattern used as the lower electrode of a capacitor so as to be buried in the second contact hole on the first conductive film pattern; and sequentially forming a high dielectric film and a third conductive film pattern used as the upper electrode of a capacitor on the second conductive film pattern.
 12. The method of claim 11 , wherein the step of forming the contact plug comprises the steps of: forming a conductive film on a substrate in which the first contact hole and the first interlayer dielectric film pattern are formed; and etching back or performing a CMP process on the conductive film.
 13. The method of claim 11 , wherein the diffusion barrier layer pattern is formed of one selected from the group consisting of Ta, Ti, W, Co, Ir, Ru, TaSi, CoSi, TiSi_(x), WSi, TiSiN, TaSiN, IrO₂, RuO₂, WN, TiN, TaN, TaAIN, and TiAIN.
 14. The method of claim 11 , wherein the first conductive film pattern is formed of a platinum group metal or an oxide conductor including the platinum group metal.
 15. A method for manufacturing a capacitor of a semiconductor device, comprising the steps of: forming a first interlayer dielectric film pattern having a first contact hole for exposing the surface of a semiconductor substrate on the semiconductor substrate; forming a contact plug buried in the first contact hole and electrically connected to the semiconductor substrate; sequentially forming a diffusion barrier layer pattern and a first conductive film pattern for exposing the first interlayer dielectric film pattern on the contact plug; forming a second interlayer dielectric film pattern having a second contact hole for exposing the surface of the first conductive film pattern on the first interlayer dielectric film pattern and the first conductive film pattern; forming a second conductive film pattern used as the lower electrode of the capacitor on the inner wall of the second contact hole and on the surface of the first conductive film pattern; and sequentially forming a high dielectric film and a third conductive film pattern used as the upper electrode of the capacitor on the second conductive film pattern.
 16. The method of claim 15 , wherein the step of forming the second conductive film pattern comprises the steps of: forming a conductive film on the overall surface of the resultant in which the second contact hole is formed; forming a material film on the overall surface of the resultant on which the conductive film is formed so as to bury the second contact hole; etching back or performing a CMP process on the material film and the conductive film so as to expose the second interlayer dielectric film pattern; and removing a material film left in the second contact hole.
 17. The method of claim 16 , wherein the material film is formed of a photoresist film or an insulating film.
 18. The method of claim 15 , wherein the step of forming the second conductive film pattern comprises the steps of: forming a conductive film on the overall surface of the resultant in which the second contact hole is formed; and performing a CMP process on the conductive film so as to expose the second interlayer dielectric film pattern.
 19. The method of claim 15 , wherein the diffusion barrier layer pattern is formed of one selected from the group consisting of Ta, Ti, W, Co, Ir, Ru, TaSi, CoSi, TiSi_(x), WSi, TiSiN, TaSiN, IrO₂, RuO₂, WN, TiN, TaN, TaAIN, and TiAIN.
 20. The method of claim 15 , wherein the first conductive film pattern is formed of a platinum group metal or an oxide conductor including the platinum group metal. 